1. Field of the Invention
The present invention relates to a display apparatus including a self-emitting light emitting element, and particularly, to a display apparatus including an organic electroluminescence element (hereinafter, “organic EL element”), which is a current control element, as a light emitting element.
2. Description of the Related Art
A voltage programming pixel circuit that sets an input data voltage in each pixel is known as a pixel circuit of an active matrix organic EL display apparatus. Such a pixel circuit generally includes a driving transistor that supplies an organic EL element with a current based on the input data voltage. However, there are variations in a threshold voltage depending on the driving transistor. Therefore, there is a problem that there are variations in the luminance of the organic EL elements even if the same input data voltage is set to each pixel. To solve the problem, Japanese Patent Application Laid-Open Nos. 2003-271095 and 2007-310311 disclose voltage programming pixel circuits that use driving transistors (N type) to cancel the influence of the variations in the threshold voltage of the driving transistors.
The pixel circuit described in Japanese Patent Application Laid-Open No. 2003-271095 includes two transistors and two capacitors, and a parasitic capacitance CL connected in parallel with a current control element is larger than a holding capacitor CS connected between a gate electrode and a source electrode of the driving transistor. Therefore, when an input video signal level is divided into the parasitic capacitance CL and the holding capacitor CS, a voltage close to the input video signal level is applied to the holding capacitor CS. As a result, it is described that the input video signal level can be reduced and that there is also an advantage in terms of power consumption.
The pixel circuit described in Japanese Patent Application Laid-Open No. 2007-310311 has a similar configuration to that of Japanese Patent Application Laid-Open No. 2003-271095. A capacitive element 3I, which is a capacitive component of a light emitting element 3D, can be larger than a holding capacitor 3C from the viewpoint of the reduction in the power consumption.
However, a large layout area is necessary to form the large parasitic capacitance CL and capacitive element 3I. Since the parasitic capacitance CL and the capacitive element 3I are arranged pixel by pixel, there is a problem that the pixel size per pixel is large.